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dlc@frii.com
Joined: 05 Nov 2003
Posts: 23
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| int_global ISR not working for INT0 interrupts |
 Posted: Tue Feb 21, 2006 1:10 pm |
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Hi all,
I'm trying to interrupt on receiving IR transmissions on the negative edge. I've set all I need and CCP1 to measure the pulses, I've set up the ISR and done the #int_global setup based on a CCS example that I modified a little. But it appears that I'm not getting the interrupt. I'll post the code here, it is pretty short.
I'm looking for what I've missed. I'm used to coding using Microchip's C18 which doesn't hide much from you so I may be not seeing something that is happening here. I've just added the setup_comparator() call, I've not tested that just yet...
thanks,
DLC
| Code: |
#include <16F628.h>
#fuses INTRC_IO,NOWDT,NOPROTECT,NOLVP,NOCPD,NOBROWNOUT,MCLR
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_B2, rcv=PIN_B1)
#use fast_io(A)
#use fast_io(B)
#define MAXBIT 13 //5 address, 7 control and one junk timing
int rise[MAXBIT];
int rW=0;
int gotOne = 0;
//save_w and save_status are at 7f and 7e which are available in ALL banks
int save_w;
#locate save_w=0x7f
int save_status;
#locate save_status=0x7e
#byte status = 3
#byte TMR1L = 0x0E
#byte TMR1H = 0x0F
#byte PIR1 = 0x0C
#byte CCPR1H = 0x16
#int_global
void isr(void)
{
#asm
//store current state of processor
MOVWF save_w
SWAPF status,W
MOVWF save_status
BCF status,5 //Set to page 0 for SFR's
BCF status,6
#endasm
rise[rW++] = CCPR1H; //save the pulse time
if (rW == MAXBIT)
{
rW = 0;
}
gotOne = 1;
TMR1L = 0;
TMR1H = 0;
#asm
// restore processor and return from interrupt
SWAPF save_status,W
MOVWF status
SWAPF save_w,F
SWAPF save_w,W
BCF PIR1,2
#endasm
}
void main()
{
int x;
int n=0;
set_tris_B(0x03);
set_tris_A(0x00);
//Turn off comparator
setup_comparator(NC_NC_NC_NC);
setup_ccp1(CCP_CAPTURE_FE); // Configure CCP1 to capture falling edge detection
setup_timer_1(T1_INTERNAL); // Start timer 1
for (x=0;x<MAXBIT;x++)
rise[x]=0;
enable_interrupts(INT_CCP1); // Setup interrupt on falling edge
enable_interrupts(GLOBAL);
printf("SONY IR decoder\n\r");
while(TRUE)
{
delay_ms(1000);
if (n)
{
output_low(PIN_A1);
n=0;
}
else
{
output_high(PIN_A1);
n=1;
}
if (gotOne)
{
for (x=0;x<MAXBIT;x++)
printf("\n\r%u %u counts ",x, rise[x]);
gotOne = 0;
}
}
}
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_________________
--
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Dennis Clark dlc@frii.com
http://www.techtoystoday.com
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newguy
Joined: 24 Jun 2004
Posts: 1903
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| Posted: Tue Feb 21, 2006 1:19 pm |
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This may not be what you're hoping for, but when I wrote a program to decode a remote control's signals there was no way I could get it to work using the CCP. I tried for a long time, then went a slightly different route:
http://www.ccsinfo.com/forum/viewtopic.php?t=21290
I ended up using the external interrupt instead. I have no idea why the CCP-based code wouldn't work, but this worked the first time.
Hope this helps. |
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Ttelmah
Guest
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| Posted: Tue Feb 21, 2006 3:04 pm |
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One thing leaps out.
When writing an int_global, it is _your_ responsibility to save every register that is used in the interrupt. Now your interrupt routine, is using an array access, so will be using the indirect access registers. You are not saving these...
The 'example', does not make any such access, so can get away without these extra saves.
Best Wishes |
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dlc@frii.com
Joined: 05 Nov 2003
Posts: 23
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| Posted: Tue Feb 21, 2006 3:09 pm |
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| Ttelmah wrote: | One thing leaps out.
When writing an int_global, it is _your_ responsibility to save every register that is used in the interrupt. Now your interrupt routine, is using an array access, so will be using the indirect access registers. You are not saving these...
The 'example', does not make any such access, so can get away without these extra saves.
Best Wishes |
Good point - While nothing else SHOULD be using those registers, CCS may be doing something I don't know about. I'll fix that goof.
DLC
_________________
--
------------------------------------
Dennis Clark dlc@frii.com
http://www.techtoystoday.com
------------------------------------ |
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dlc@frii.com
Joined: 05 Nov 2003
Posts: 23
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| Posted: Tue Feb 21, 2006 3:10 pm |
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All,
One goof I made in the subject line: I said INT0 IRQ, I meant CCP1 IRQ.
oops,
DLC
_________________
--
------------------------------------
Dennis Clark dlc@frii.com
http://www.techtoystoday.com
------------------------------------ |
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Ttelmah
Guest
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| Posted: Tue Feb 21, 2006 3:32 pm |
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| dlc@frii.com wrote: | | Ttelmah wrote: | One thing leaps out.
When writing an int_global, it is _your_ responsibility to save every register that is used in the interrupt. Now your interrupt routine, is using an array access, so will be using the indirect access registers. You are not saving these...
The 'example', does not make any such access, so can get away without these extra saves.
Best Wishes |
Good point - While nothing else SHOULD be using those registers, CCS may be doing something I don't know about. I'll fix that goof.
DLC |
The rise[x] access in main, will use the indirect addressing registers as well.
Best Wishes |
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Guest
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| Posted: Mon Feb 27, 2006 1:14 pm |
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| newguy wrote: | This may not be what you're hoping for, but when I wrote a program to decode a remote control's signals there was no way I could get it to work using the CCP. I tried for a long time, then went a slightly different route:
http://www.ccsinfo.com/forum/viewtopic.php?t=21290
I ended up using the external interrupt instead. I have no idea why the CCP-based code wouldn't work, but this worked the first time.
Hope this helps. |
As it turns out, after I fixed a couple of goofs with my wiring, and recode my ISR to handle saving variables and clean up a few more odds-n-sods things... The ISR works just fine. I added a Timer1 overflow interrupt as well to detect timeouts so that I can properly re-sync if I need to get the next command. It all works just fine now. Thanks all that helped out.
I am working with a toy remote for my 4 year old to animate one of his toys and it has a "sort of RC5" output with oddities that mean that I can't assume any particular command pulse length, it's variable. This code handles it just fine.
DLC |
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